LANDSHAPING FOR IMPROVING THE LIVELIHOOD OF COASTAL COMMUNITIES IN VULNERABLE AREAS
More than half of the world population lives within 100 km of the sea, and depend directly or indirectly on coastal and marine ecosystem for their livelihood. However, these ecosystems are being increasingly impacted by anthropogenic perturbations and natural hazards including climate change. Major processes affecting these fragile ecosystems and livelihood of people include sea water intrusion, coastal erosion, waterlogging and salinization. The condition was deeply aggravated in the Indian Ocean region after December 2004 tsunami. Therefore, it is imperative to develop innovative and adaptive methods for conservation and sustainable utilization of coastal resources.
In these areas land shaping such as broad bed and furrow (BBF) system and rice-fish culture is a viable option to cope with the natural hazards occurring due to sea water intrusion and climate change. To evaluate the feasibility and impact of such systems in the lowlying areas a study was under taken in the tropical islands of Andaman and Nicobar, India. It encompasses assessment of the impact of tsunami and water logging on soil characteristics and effectiveness of some of the technological interventions in restoring the productivity of selected degraded areas. BBF system is made by digging the waterlogged land to make furrow of 6 m width and 2 m deep and raising the land 1 m height and 4 m width using the cut soil in a way that there is raised bed and furrow alternatively.
This system made in the low-lying degraded coastal areas improved the drainage of the raised beds which simultaneously resulted in harvesting of rain water in the furrow. The surface soil pH of the beds was slightly acidic (6.36) whereas it was significantly lower (5.8) for the surrounding soils. Moreover, the salinity level in the beds of BBF made in water logged soil was much lower (1.5 dSm-1) than under saline soils (>2.0 dSm-1). The salt concentration in saline soils remained higher throughout the dry season but after onset of monsoon the salt level has decreased. Significantly lower Na+, Ca2+ and SAR values were observed in the beds of BBF than both the initial value and the surrounding areas. The harvested rainwater in the furrows (4476 m3 ha-1) could be used for providing life saving irrigation for crops grown during dry periods on the beds and even in the adjoining areas. The system also provided ample scope for crop diversification and the cropping intensity increased upto 170 - 218 % while it was only 90 % in no intervention areas but cultivated. The combined effect of higher crop, fish and water productivity resulted in higher annual net income for BBF system due to round the year crop cultivation and higher fish productivity. BBF system made in water logged soil was highly significant than BBF in acid saline condition followed by bunded areas and degraded land.
